The breaker, like most has loose terminals which slide over the bus bar. The terminals on this breaker were so sloppy that they angled themselves in such a way during install that they would not line up with buss bar, no matter how I jiggled it. I finally slid small pieces of plastic beside the terminals to help keep them aligned. Then it slid in. I have not tested it yet, as it is to an ac condenser and it is 20° here. I'm hoping there are no issues with the operation of it.